Resource allocation model for bacterial shape control under growth perturbations*

Single bacterial cells adapt their growth rates and morphologies to changes in environmental conditions in order to optimize their fitness for proliferation. Control of cell size demands making tradeoffs between cellular resources allocated towards growth and division. Understanding the nature of these tradeoffs remains an outstanding challenge. Here we propose a coarse-grained theory for how bacteria allocate their molecular resources to regulate their cell shapes and growth rates in varying nutrient environments and antibiotic induced perturbations. We propose that a balanced tradeoff between ribosomal resources allocated towards growth and division determines the control of bacterial cell volume and surface area. The results from our model are in excellent quantitative agreement with available experimental data on single-cell growth and shape under nutrient and translational perturbations. By calibrating our model with experimental data, we further predict that a combination of antibiotics that induce cell filamentation and inhibit translation may be more efficient in bacterial killing.